1. Field of the Invention
The present invention relates to a content-transmitting apparatus, which transmits contents via a network, a content-receiving apparatus, which receives contents, and an art related thereto.
In this specification, “contents” means an arbitrary combination of a moving picture, a still picture, a text, or a pictograph, and “content data” means digital data that the above-mentioned contents are recorded in arbitrary formats.
2. Description of the Related Art
By using network communication, such as an E-mail and FTP, not only can character string data be transmitted, but also contents can be transmitted from a transmission source to a transmission destination; therefore, communication can be broaden.
People, who have technical knowledge, have taken the lead and have used such data communication up to the present.
An environment, which is capable to connect to a network such as the Internet, has widely spread to each home; therefore, chances for people such as the elderly and children who are not well versed in the network environment to receive data, have increased.
For this reason, there is need for improvements in data transmission that make data transmission easy than conventional systems.
Additionally, there is a need for a system that can transmit contents via a network, but that is less costly, has a nature of instancy and is advantageous when compared to a a recording medium, such as a disk or a tape that is sent physically.
It is considered that the system should be widely used in daily life. For example, in such a case where parents can take pictures of their child's graduation ceremony, create contents and then transmit the contents to grandparents (elderly people) who live at distant locations.
Currently, in order to transmit contents via a network, contents are transmitted as an attached E-mail, and the contents attached to the E-mail are reproduced by computers and cellular phones at the receiving side.
Conventional Receiving Side facilities are described in the following published Japanese Patent Application Laid-Open No. 2001-125851 (patent reference No. 1).
In this prior art, as shown in a FIG. 6 (a), not only is an attached file such as contents, but also an attached file header including transmitted time information and created date information of the attached file is attached and the E-mail is transmitted to a transmission destination.
At the receiving side, the attached file (e.g. contents) is reproduced based on the transmitted time information and created date information of the attached file header.
By doing so, even if a transmission destination does not know the right order of reproduction, contents are reproduced in the order of reproduction specified by a transmission source; therefore, convenience can be improved comparing to simply attaching a plurality of contents to an E-mail.
Additional related prior art is disclosed in published Japanese Patent Application Laid-Open No. 2002-7282 (patent reference No. 2).
As shown in FIG. 6 (b), a transmission source adds information of specified transmission date to an E-mail, and transmits the E-mail.
A transmission destination is not notified of completion of receiving immediately after transmission, but after waiting purposely until it becomes the specified transmission date, the transmission destination is notified of the completion of receiving the data.
Thereby, the transmission destination has received the E-mail exactly on the date specified.
The prior art according to patent reference No. 2 is useful when notifying date has an important meaning, such as a birthday message and a wake-up call.
As mentioned on the above, since a transmission destination is not necessarily well versed in complicated operation of a personal computer etc., the transmission destination should be able to reproduce contents with easy operations as much as possible.
However, both patent references No. 1 and No. 2 have following problems, indicating that the prior arts thereof are inadequate.
The prior art according to patent references No. 1 is on the assumption that order of reproduction of contents sent with an attached file header is specified in the.
Therefore, contents whose order of reproduction can be specified by the attached file header are only the contents sent with this attached file header. Contents transmitted prior to transmission time of the attached file header from the same transmission source to the same transmission destination can not be specified.
According to the art, specifying order of reproduction of contents including contents transmitted in the past have to attach the contents transmitted in the past to an attached file header again, and transmit again.
Since contents generally have large size of data comparing to character string data, a load of network increases and longer time is necessary in order to complete sending and receiving when transmitting contents transmitted in the past again.
Furthermore, the same contents is stored multiplexingly in a recording unit of a content-receiving apparatus; therefore, it is useless and can be a factor pressing the capacity of the recording unit of the content-receiving apparatus.
In an E-mail, the prior art described in patent reference No. 2 has a point that only contents that is sent with an E-mail can specify reproducing date information. This point is similarly described by patent reference No. 1.
Therefore, there exits the same problem that patent reference No. 1 has.
However, in patent reference No. 2, the completion of receiving of an E-mail is intentionally hidden from a transmission destination until the time specified by the date information.
Therefore, it looks like that the contents received in the past is reproduced from the time specified by the date information.
However, this is only what has delayed the time to reproduce purposely.
An E-mail and contents are still sent together.
After all, in an E-mail, although a transmission destination has received in the past comparing to the time of transmission of an E-mail, the time to reproduce can not be specified for contents, which are not transmitted with the E-mail.